Mario Herrera has a B.A. in Education and an M.A. in Teaching English as a Foreign Language. He specializes in teaching English to young learners. He has authored or co-authored several bestselling ELT programs worldwide, including Pockets and Big Fun for pre-school; Backpack, and Big English and Big English Plus for primary school. Mr. Herrera has also been involved in teacher training for 28 years and travels internationally on behalf of Pearson ELT.